Drug Interaction Report

Dong Quai and Dalteparin Injection: Interaction Details

Name: Dong Quai and Dalteparin Injection Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Dong Quai and Dalteparin Injection interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Dalteparin Injection

Fragmin Fragmin®

Dong Quai

No brand names on record

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Moderate

Can be significant — usually manageable with monitoring.

Minor

Moderate

Major

Contraindicated

How we grade severity & evidence

Severity levels

Contraindicated: These should generally not be used together.
Major: Potentially serious — often needs a change or close monitoring.
Moderate: Can be significant — usually manageable with monitoring.
Minor: Usually limited clinical impact.

Evidence grades

Established: Well documented — supported by controlled studies or strong clinical data.
Probable: Good supporting evidence, though not definitively proven.
Suspected: Some evidence suggests this interaction, but it is not well established.
Possible: Limited or conflicting evidence; the interaction may occur.
Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 13 documented Dong Quai interactions, 13 are rated moderate — including this one.

Onset

delayed

Evidence

theoretical

Severity

Moderate

What happens

Increased risk of bleeding

Interaction Deep Dive

Theoretically, dong quai may increase the risk of bleeding when taken with low molecular weight heparins. One patient taking dong quai with warfarin presented with excessive bruising and an International Normalized Ratio (INR) of 10, within 1 month of beginning dong quai¹; another patient taking dong quai with warfarin presented with an INR of 4.9 yet was asymptomatic ². In a study of 96 patients, intravenous dong quai significantly prolonged prothrombin time compared with dextran ³. Dong quai contains coumarin derivatives and components that may inhibit platelet aggregation ²⁴.

Why it happens (mechanism)

Dong quai contains coumarin derivatives and may also inhibit platelet aggregation

Common questions

Can I take Dong Quai and Dalteparin Injection together?

Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.

How serious is the Dong Quai and Dalteparin Injection interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "delayed". Effects tend to build up gradually over days to weeks.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

Does my dose of Dong Quai or Dalteparin Injection need adjusting while I take them together?
What symptoms should prompt me to call you or my prescriber right away?
Does the timing of my doses matter for this combination?
Is there anything you'd monitor while I'm on both?

References (4)

Ellis GR & Stephens MR: Minerva. BMJ 1999; 319:650.
Page RL & Lawrence JD: Warfarin potentiation by dong quai. Pharmacotherapy 1999; 19:870-876.
Junjie T & Huaijun H: Effects of Radix Angelicae Sinensis on hemorrheology in patients with acute ischemic stroke. J Tradit Chin Med 1984; 4:225-228.
Ko FN, Wu TS, Liou MJ, et al: Inhibition of platelet thromboxane formation and phosphoinositides breakdown by osthole from Angelica pubescens. Thromb Haemost 1989; 62:996-999. DOI

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HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

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